Assigetob to westebn electric



u TED sra'rns PATENT OFFICE.

ALFRED n. DYSON, or MonTotaIR, NEW JERSEY, ASSIGNOR T WESTERN ELECTRIC COMPANY, or new YORK, N. Y., A conrona'rron or ILLINOIS.

TELEPHONE SYSTEM.

Application filed March 31, 1914.

Z '0 all whom it may concern:

and State of New Jersey, have invented. a

certain new and useful Improvement in Telephone Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to automatic telephone systems. I

The invention is applied to a systemin which automatic connecting switches located at a central office are controlled over two line wires leading to a subscribers station Without the aid of a third conductor.

. The object of this invention is to provide means for variously controlling the switches of the system over these two line conductors.

The particular classes of control here provided for are the movement of the contacts of a switch to a desired position, the maintenance of the switch in this desired posi tion during the control of other switches and the return of the switch to its normal position. The means bywhich the foregoing controls are accomplished is a,pair of ratchet wheels, which, when through the agency of electromagnets, funetion to alter circuit conditions after the lapse of a predetermined interval. This interval may be varied by slight changes in the design of said ratchet wheels as Will hereafter befully described.-

5 The invention is illustrated in the accompanying drawings in which- Figure 1 is a front View of' the mechanism for obtaining the desired time; interval in its normal position, and Fig. 2 is a circuit dia- 0 gram showing the portion of a ,telephone system in which this mechanism is used.

In Fig. 1 electromagnets 15' and 24 are I mounted by means of brackets 81, 82. Upon brackets 81, 81 are pivotally mounted arma 5 tures 12 and 13 which carry cams 70 and 71,

respectively. Plates 75, 75 have mounted thereon by means of a pin, springs 73, 74. Said springs 73, 74 have a slot cut in one end through which cams 70 and 71 extend and l are held in engagement with said slot by means of springs 86, 86. Upon the forward stroke of armatures 12 and 13 the cams 70 and 71 are pulled through the slot until they are on the opposite side of springs 73, 74 to that which they are normally held. Said Specification of Letters Patent.

actuated.

Serial No. 828,586.

when actuated in either a forward or backward direction. The tension of the outside springsof contacts 16 and 25 is in a direc- Patented Dec. 14, 1915. I

tion away from electromagnets 15 and 24,

which causes said springs to recede from theirnormal contact and to follow springs 73, 7 4 until springs 73., 74 come to rest against stop pins 83, 83. When these contacts are opened, the circuit for electromagnets 15 and 24 is broken, thus allowing springs 87, 87 to restore armatures 12 and 13 to normal position, which again close contacts 16 and 25. It followsthat the cams 70 and 71, together with springs of contacts 16 and 25 and springs 73, 74 constitute an interrupter for electromagnets15 and 24. y

Pawls 10 and 11 are pivotally mounted near the extreme end of armatures 12 and 13 and are held in position by springs 9, 9 so as to engage the teeth of ratchet Wheels 1 and 2, when said armatures 12 and 13 are attracted upon the energization of electromagnets 15 and 24. The movement of pawls 10 and 11 is limited by 'stop pins 6, 6 and 7, 7.

Ratchet Wheels 1 and 2 are mounted in.

operative relation with pawls 11 and 12 by means of pivots. Said wheels 1 and 2 are restored by springs 5, 5. In case ratchet wheel 1 has been restored by spring 5, pawl 4 engages one of the teeth of ratchet wheel 2. When ratchet wheel 1 is in this position, pawl 11 of arma-' ture 13, upon the energization of electromagnet 15, engages one of the teeth of said ratchet Wheel 1, pawl 4 is moved out of engagement with the teeth of wheel 2 by means of cam 85 formed on the periphery of said ratchet wheel 1, and is heldin that position until said ratchet wheel 1 is again restored by spring 5. The rotation of ratchet Wheel 1 step by step in a c'ounter-cloclnvise direction, is obtained by means of the interrupter composed of contact 16, spring 73 and cam rotation of ratchet wheel The interval of.

time during which contact 19 .remains closed, after ratchet wheel 1. commences to rotate, is predetermined and may be .yaried 'by changing the size of cam 84. It may be a clockwise direction upon the energization and deenergization of electromagnet 24, m

a manner similar to the rotation of ratchet wheel 1, as described above. I When said ratchet wheel 2 is rotated the first step, cam 90 causes pawl 3 to become disengaged from the j teeth of ratchet wheel 1, which allows, it to return to be restored by means of spring 5. As ratchet wheel 2 continues to rotate, cam

91 passes beyond and out of engagement i with the spring of'contact 22, which permits said spring to engage with its mate, thus closing contact 22. vPlll 8, by engaging with the spring .ofcontact 18, opens said contact.

' Said pi'nlSis so positioned that contact, 22

91 and position of pin 8.

is closed before contact spring 18 is opened.

The time required for the closing and open- 30,

mg of said contacts is predetermined and may be varied by changing the ewe of cam The parts illustrated in Fig. 1 which enten, into the electrical circuits of the system are represented in Fig. 2 by numerals 15 16, 18, 19, 22, 24 and 25. In this figure the calling subscribers'station 30 is provided with the usual transmitter and receiver and with a controlling device having contacts 31 arranged to open the circuit of the line conductors 32 and 33 in the transmission of a signal. This line is connected through suitable switch contacts With the conductors of a" selector switch circuit wherein the line conductor 32 extends through one winding of relay 34 to the live pole of centralbattery 35, and'line conductor 33 extends through another winding of relay 34- to the ground pole of said battery. The preliminary closure of'the line at the subscribers station I by the removal of the subscribers receiver from its book, energizesrelay 34, causing the closure of its front'contacts 36 and the consequent energization of relay 37. Atjthe same time electromagnet 24 is energized by the following circuit: ground, front contacts 36 of relay 34, contacts 18, 2 5, coil of electromagnet 24, to battery. This circuit is v magnet 24 is closed for a sufficient interval interrupted by the opening and closing of contact 25 under the influence of armature 12 in a manner as previously described.

The energization and deenergization of electromagnet 24 rotates ratchet wheel 2 out of 1 normal position,'-thus causing the disengagement of pawl 3 from the teeth of ratchet wheel 1, which allows said ratchet wheel to be restoredby means ofspring 5. This establishes a locking circuit for relay 37 through its front contact38 and contact 19. Electromagnet 24, through the interruption of its circuit,continues to rotate ratchet wheel 2 until battery is removed by the digits of they desired subscribers number.

At the first interruption, relay 34 releases its armatures. The first release completes a circuit throughback contacts 40 of relay 34, front contacts 43 of relay 37, contact 16 and the coil of electromagnet l5, this-circuit including the battery 35. The periodic closures of this circuit and consequent energizations of electromagnet 15, causes ratchet wheel 1- to be rotated momentarily, thus. 5

causing pa wl 4 to be disengaged from the teeth of ratchet wheel 2, which permits said ratchet wheel 2 to return to normal position under the influence of spring 5. While the interruptions are being sent over the line,

electromagnets 15 and 24 are energized and deenergized in rapid succession, the control of each'by the otherbeing such that neither ratchet may 'be rotated. more than one or I two steps before being released by the operation of the other. This oscillation continues until the interruptions cease, whereupon ratchet wheel 2 is rotated. ofi' normal x-At each denergization of relay 34, the back contacts 42 of thatv relay complete a circuit through front contacts 41' of relay 37, conductor 44, contacts 45 and the coil of primary stepping magnet 46 to battery. Current in this path energizes the stepping magnet 46 once for each time that the circuit is interrupted at subscribersstation 30. The switch controlled in its primary movement by stepping magnet 46 is of a type in which each energization and deenergization of the primary magnet 46 moves a. set of contact wipers-in front of a group 'or rowof contacts; thus one energization of the primary magnet 46 places the Wipers in front of one group of the contacts, two energizations and deenergizations in front of another and so on, the number of groups'usually being ten.

At the completion of the first series of lnterruptlons, the circuit through electrorotation of said ratchet wheel 2 by breaking 1 the circuit of electromagnet 24. A circuit is now completed through the impedance coil '39, contact 22, conductor 47, contactsadapted to move the contact wipers over the contacts of the group which has been picked out by the previous actuation of magnet 46, the circuit 53 being made and broken by its own contacts 52 so long as the relay 50'remains in its actuated condition. Upon the first actuation of secondary magnet 53, the wipers 54 were moved into contact with the first of the series of contacts in the particular group which had been picked out by directive actuation of primary magnet 46. These contacts are connected with trunk lines extending to other switches and as will be hereafter explained, the contacts connecting with busy trunk lines will have a guarding potential thereon to indicate the busy condition. Considering that the first few contacts to be reached by the privatev wiper 54 are thus guarded by a ground po tential, a circuit is completed through con ductor 55, front contacts 56 of relay 37 front contacts 57 and coil of relay 50 to battery. Current in this part maintains the actuation, of relay 50, whichmaintains the circuit through the secondary stepping magnet 53 until the private wiper 54 arrives upon a non-grounded trunk contact, whereupon the circuit in the path just described is interrupted and the relay 50 resumes its normal position, opening the circuit of the,

secondary stepping magnet 53 and closing its own back contacts 58, thus putting ground potential upon wiper 54 and the contact of the trunk just selected to guard this trunk against its selection by other switches. It maybe stated here that the secondary oil"- normal contacts 45 and 49 were interrupted upon thefirst actuation'of secondary stepping magnet 53. The next series of inter ruptions which are made by the controller 31 at the subscribers station in designating the second digit of the desired number similarly denergizes the relay 34 but this time, instead of controlling the circuit of the se lector switch shown in the drawings, the circuit of the next switch in the series will be controlled. Primary magnet 46 and secondary magnet 53 arenot actuated because their respective circuits are broken through the opening of secondary ofi' normal contacts 45 and 49 as described above. As before, the electromagnet 15 will be energized by the first deenergization of relay 34, which restores ratchet wheel 2 to normal position, and at each energization and denergization. of relay 34 ratchet wheels 1 and 2 will oscillate as herein previously described. At each definergization of relay .34 a circuit will be completed through the back contacts 42, front contacts 41 of relay 37, conductor 44, back contacts 60 of relay 50, wiper 61, conductor 62 and a magnet of the next switch in the series. At the lapse of a predetermined interval as before described, contact 22 is closed, which completes a circuit through impedance 39, contact 22, conductor 47, back contacts 63 of relay 50, Wiper 64, conductor 65 and a relay or electromagnet of the next switch in the series to be controlled. This succeeding switch may be of the type disclosed in the patent to me, N 0. 975,608 of N ovember. 15, 1910.

In order to return the switch to its normal position, the circuit at the subscribers scribed. The rotating of ratchet wheel 1,-

after the lapse of a predetermined time. opens contact 19. This breaks the locking circuit for relay 37 and permits that relay to return to normal, closing its back contacts 69. A circuit is thus established through back contacts 42 of relay 34, back contacts 69 of relay 37, primary ofl normal contacts 48 and coil of relay 50 to battery. The actuation of relay 50 again brings the secondary stepping magnet 53 into circuit which, through its pawl, continues the movement of wipers 54,61 and 64 over the contacts until the switch has been moved to its extreme secondary position beyond the last contact of the group. At this point the primary retaining pawl is tripped, permitting the switch to return to its normal position so far as its primary movement is concerned. At the end of this primary movement, the secondary retaining pawl is tripped, permitting the switch to return to its normal position so far as the secondary movement is concerned. The interruption of contacts .56 of relay 37, removed the guard potential 1 from private wiper 54, and caused the release of the next succeeding switch in the series. All of the apparatus is then returned to its normal position and is in readiness for a second call, the ratchet Wheels 1 and 2 assuming the position shown in Fig. 1.

Ratchet wheel 1 remains in this position until restored by the spring 5 when ratchet wheel 2 is rotated upon the removal of the receiver at subscribers station 30, when initiating anothercall. p I

It is to be understood that the apparatus of Fig. jlinay be applied to 'many other types of system than that shown in Fig. 2, and that modifications may be made in the apparatus itself without departingfrom the spirit or scope of this invention.

What is claimed is:

1; Ina telephone system, thecombination with a telephone line, of an interrupter mechanism at the subscribers station of said line, a switch at the central oflice, a primary controlling magnet, a secondary controlling magnet, a controlling relay for said magnets under the control of said substation" in-' terrupter, and a circuit changing device comprising two electromagnetic interrupters and a ratchet mechanism actuated thereby, said ratchet mechanism functioning-to alter circuit conditions after the last deem ergization of said controlling relay to switch the current controlled by said relay from one of. said controlling magnets to the other.

' 2. In a telephone system, the combination with a telephone line, of an interrupter said line, a switch at. the central office, a controlling relay for said switch under the control of said substation --interrupter, two electromagnetic interrupters,

ratchet wheels actuated by said interrupters "and so positioned that the rotation of one releases the other if the latter is in an olfnormal position, one or the other of said ratchet wheels being always responsive to said controlling relay.

3. In a telephone system, the combination with a telephone line, of an interrupter mechanism "at the subscribers substation of said line, a switch at the central office, a controlling relay for said switch-said relay being energized and deenerg'ized by the in terruption produced at the subscribers substation, two stepby step ,circuit changing interrupters, one of said interrupters being responsive to, said controlling relay when said relay is energized, and the other being responsive when said relay is deenergized.

4:. In a telephone system, an impulse transmitter, a relay controlled thereby, a '55 pair of electromagnetic circuit controlling devices mechanically operating upon one another whereby each when operated releases the other, an operating circuit forone of said electromagnetic devices closed 'by the actuation of said relay and an operating circuit for the other electromagnetic device closedby deenergization of said relay.

5." In an automatic telephone system, the

combination with a selector switch, of a primary controlling magnet and a secondary ary contacts, a relay for controlling said 'mary controlling magnet and areleasing mechanism at the subscribers substation of a pair of terrupters.

Ynism functioning to bring the secondary magnetinto action at a predetermined time after the last action of the primary magnet.

6. In a telephone system, the combination with a selector switch, a set of movable contacts for said switchand a plurality of sets of stationary contacts, an electromagnet for causing the step-by-step movement of the movable contacts to various sets of station.-

electromagnet, and a circuit changer includ ing two electromagnetic interrupters having associated therewlth a ratchet mechanism also controlled by saidrelay and adapted to remove said eiectromagnet -from the control of said relay at a predetermined time after the. last control of said magnet 'by said relay. 7. In an automatic telephone system, the combination with a selector switch, of a primagnet for said switch, .a relay, initially causing the completion of the circuit of the primary magnet each time it releases its armatures, and a switching device including two electromagnetic interrupters, a ratchet mechanism associated therewith, said switching device acting after a predetermined time from the last release of the armatures of said relay to place the releasing magnet under the control of said relay so as to return the selector switch to its normal position if trolled by said cams and circuits therethrough opened and closed at a predetermined time after said ratchet wheels are rotated by means of said electromagnetic in- 10. Incombination with a circuit changing device, two electromagnetic interrupters,

a pair of ratchet wheels so positioned that the rotation of one releases the otherif the latter is in an ofi-normal position, cams op- 12,)-

erated by said ratchet wheels, contact springs operated by said cams which make and break contact at a predetermined time after said ratchet wheels are rotated by means of said electromagnetic interrupters. 139

the lapse of a'predetermined time to prevent further rotation of the ratchet wheel controlled by said interrupter.

12. The combination with a circuit chang-.

ing device, two electromagnetic interrupter-s, a pair of ratchet wheels actuated thereby,

contact springs controlled by said ratchet wheels and means carried by one of said ratchet wheels for opening the circuit there- 15 through of one of said interrupters at the lapse of a predetermined time to' prevent further rotation of the ratchet wheel controlled by said interrupter.

In Witness whereof, I hereunto subscribe 20 my name this 28 day of March A. D. 1914.

' ALFRED H. DYSON.

Witnesses:

E. EDLER, I NANoN E. TUTHILL. 

